1 // SPDX-License-Identifier: GPL-2.0+
3 * Helpers for controlling modem lines via GPIO
5 * Copyright (C) 2014 Paratronic S.A.
9 #include <linux/device.h>
10 #include <linux/irq.h>
11 #include <linux/gpio/consumer.h>
12 #include <linux/termios.h>
13 #include <linux/serial_core.h>
14 #include <linux/module.h>
15 #include <linux/property.h>
17 #include "serial_mctrl_gpio.h"
20 struct uart_port *port;
21 struct gpio_desc *gpio[UART_GPIO_MAX];
22 int irq[UART_GPIO_MAX];
23 unsigned int mctrl_prev;
31 } mctrl_gpios_desc[UART_GPIO_MAX] = {
32 { "cts", TIOCM_CTS, false, },
33 { "dsr", TIOCM_DSR, false, },
34 { "dcd", TIOCM_CD, false, },
35 { "rng", TIOCM_RNG, false, },
36 { "rts", TIOCM_RTS, true, },
37 { "dtr", TIOCM_DTR, true, },
40 void mctrl_gpio_set(struct mctrl_gpios *gpios, unsigned int mctrl)
42 enum mctrl_gpio_idx i;
43 struct gpio_desc *desc_array[UART_GPIO_MAX];
44 int value_array[UART_GPIO_MAX];
45 unsigned int count = 0;
50 for (i = 0; i < UART_GPIO_MAX; i++)
51 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
52 desc_array[count] = gpios->gpio[i];
53 value_array[count] = !!(mctrl & mctrl_gpios_desc[i].mctrl);
56 gpiod_set_array_value(count, desc_array, value_array);
58 EXPORT_SYMBOL_GPL(mctrl_gpio_set);
60 struct gpio_desc *mctrl_gpio_to_gpiod(struct mctrl_gpios *gpios,
61 enum mctrl_gpio_idx gidx)
66 return gpios->gpio[gidx];
68 EXPORT_SYMBOL_GPL(mctrl_gpio_to_gpiod);
70 unsigned int mctrl_gpio_get(struct mctrl_gpios *gpios, unsigned int *mctrl)
72 enum mctrl_gpio_idx i;
77 for (i = 0; i < UART_GPIO_MAX; i++) {
78 if (gpios->gpio[i] && !mctrl_gpios_desc[i].dir_out) {
79 if (gpiod_get_value(gpios->gpio[i]))
80 *mctrl |= mctrl_gpios_desc[i].mctrl;
82 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
88 EXPORT_SYMBOL_GPL(mctrl_gpio_get);
91 mctrl_gpio_get_outputs(struct mctrl_gpios *gpios, unsigned int *mctrl)
93 enum mctrl_gpio_idx i;
98 for (i = 0; i < UART_GPIO_MAX; i++) {
99 if (gpios->gpio[i] && mctrl_gpios_desc[i].dir_out) {
100 if (gpiod_get_value(gpios->gpio[i]))
101 *mctrl |= mctrl_gpios_desc[i].mctrl;
103 *mctrl &= ~mctrl_gpios_desc[i].mctrl;
109 EXPORT_SYMBOL_GPL(mctrl_gpio_get_outputs);
111 struct mctrl_gpios *mctrl_gpio_init_noauto(struct device *dev, unsigned int idx)
113 struct mctrl_gpios *gpios;
114 enum mctrl_gpio_idx i;
116 gpios = devm_kzalloc(dev, sizeof(*gpios), GFP_KERNEL);
118 return ERR_PTR(-ENOMEM);
120 for (i = 0; i < UART_GPIO_MAX; i++) {
121 enum gpiod_flags flags;
125 /* Check if GPIO property exists and continue if not */
126 gpio_str = kasprintf(GFP_KERNEL, "%s-gpios",
127 mctrl_gpios_desc[i].name);
131 present = device_property_present(dev, gpio_str);
136 if (mctrl_gpios_desc[i].dir_out)
137 flags = GPIOD_OUT_LOW;
142 devm_gpiod_get_index_optional(dev,
143 mctrl_gpios_desc[i].name,
146 if (IS_ERR(gpios->gpio[i]))
147 return ERR_CAST(gpios->gpio[i]);
152 EXPORT_SYMBOL_GPL(mctrl_gpio_init_noauto);
154 #define MCTRL_ANY_DELTA (TIOCM_RI | TIOCM_DSR | TIOCM_CD | TIOCM_CTS)
155 static irqreturn_t mctrl_gpio_irq_handle(int irq, void *context)
157 struct mctrl_gpios *gpios = context;
158 struct uart_port *port = gpios->port;
159 u32 mctrl = gpios->mctrl_prev;
163 mctrl_gpio_get(gpios, &mctrl);
165 spin_lock_irqsave(&port->lock, flags);
167 mctrl_diff = mctrl ^ gpios->mctrl_prev;
168 gpios->mctrl_prev = mctrl;
170 if (mctrl_diff & MCTRL_ANY_DELTA && port->state != NULL) {
171 if ((mctrl_diff & mctrl) & TIOCM_RI)
174 if ((mctrl_diff & mctrl) & TIOCM_DSR)
177 if (mctrl_diff & TIOCM_CD)
178 uart_handle_dcd_change(port, mctrl & TIOCM_CD);
180 if (mctrl_diff & TIOCM_CTS)
181 uart_handle_cts_change(port, mctrl & TIOCM_CTS);
183 wake_up_interruptible(&port->state->port.delta_msr_wait);
186 spin_unlock_irqrestore(&port->lock, flags);
191 struct mctrl_gpios *mctrl_gpio_init(struct uart_port *port, unsigned int idx)
193 struct mctrl_gpios *gpios;
194 enum mctrl_gpio_idx i;
196 gpios = mctrl_gpio_init_noauto(port->dev, idx);
202 for (i = 0; i < UART_GPIO_MAX; ++i) {
205 if (!gpios->gpio[i] || mctrl_gpios_desc[i].dir_out)
208 ret = gpiod_to_irq(gpios->gpio[i]);
211 "failed to find corresponding irq for %s (idx=%d, err=%d)\n",
212 mctrl_gpios_desc[i].name, idx, ret);
217 /* irqs should only be enabled in .enable_ms */
218 irq_set_status_flags(gpios->irq[i], IRQ_NOAUTOEN);
220 ret = devm_request_irq(port->dev, gpios->irq[i],
221 mctrl_gpio_irq_handle,
222 IRQ_TYPE_EDGE_BOTH, dev_name(port->dev),
225 /* alternatively implement polling */
227 "failed to request irq for %s (idx=%d, err=%d)\n",
228 mctrl_gpios_desc[i].name, idx, ret);
235 EXPORT_SYMBOL_GPL(mctrl_gpio_init);
237 void mctrl_gpio_free(struct device *dev, struct mctrl_gpios *gpios)
239 enum mctrl_gpio_idx i;
244 for (i = 0; i < UART_GPIO_MAX; i++) {
246 devm_free_irq(gpios->port->dev, gpios->irq[i], gpios);
249 devm_gpiod_put(dev, gpios->gpio[i]);
251 devm_kfree(dev, gpios);
253 EXPORT_SYMBOL_GPL(mctrl_gpio_free);
255 void mctrl_gpio_enable_ms(struct mctrl_gpios *gpios)
257 enum mctrl_gpio_idx i;
262 /* .enable_ms may be called multiple times */
266 gpios->mctrl_on = true;
268 /* get initial status of modem lines GPIOs */
269 mctrl_gpio_get(gpios, &gpios->mctrl_prev);
271 for (i = 0; i < UART_GPIO_MAX; ++i) {
275 enable_irq(gpios->irq[i]);
278 EXPORT_SYMBOL_GPL(mctrl_gpio_enable_ms);
280 void mctrl_gpio_disable_ms(struct mctrl_gpios *gpios)
282 enum mctrl_gpio_idx i;
287 if (!gpios->mctrl_on)
290 gpios->mctrl_on = false;
292 for (i = 0; i < UART_GPIO_MAX; ++i) {
296 disable_irq(gpios->irq[i]);
299 EXPORT_SYMBOL_GPL(mctrl_gpio_disable_ms);
301 MODULE_LICENSE("GPL");